4. Open the front-panel door and turn the vent valve one turn counterclockwise.
5. Listen for the sound of the turbo pumps spinning down and wait until the
turbomolecular pump has completely stopped. Leave the vent open for about
10 minutes to allow the pressure to equilibrate.
6. Close the vent valve by turning it clockwise fully.
Turning Off the Mass Spectrometer with Nitrogen
Purge
Purging the vacuum manifold with nitrogen after the trap has partially cooled can
reduce the shutdown time.
WARNING:
BURN HAZARD
Allow heated zones to cool before disassembly.
1. Shut down the mass spectrometer through the Startup/Shutdown tab in
System Control. Click the Shut Down button in the upper left corner of the
screen. The heaters will be turned off and the speed of the turbo pump will
be gradually reduced to 35% of full speed. It will take a few minutes for this to
take place.
2. Open the front door and attach a source of nitrogen at 5 PSI pressure or less
through a polyurethane tube to the barbed fitting at the center of the vent
valve.
3. Once the pump spin speed has reached 35% and the trap temperature has
fallen to 150 °C, exit the system control program, and then shut off the
turbomolecular pump, foreline pump, and all electronics by turning off the
main power switch on the back panel.
4. Disconnect the 4000 MS power cord.
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Summary of Contents for 4000 GC
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